BANGKOK — A military court in Thailand on Wednesday sentenced a man to 20 years in prison in the Southeast Asian country’s latest conviction on charges of insulting the monarchy.

The legal monitoring group iLaw said that Tara, whose last name it withheld to protect his privacy, was convicted and sentenced on six counts of lese majeste, as the offence is known, for uploading online six audio files made by a critic of the monarchy.

It said that Tara has been held without bail since January 2015 and pleaded guilty to receive a more lenient sentence. The court accordingly reduced the penalty for each count from five years to 3 1/2 years’ imprisonment. The maximum penalty per count is 15 years.

According to iLaw, the court said that Tara had “wronged the monarchy, which greatly affects the people’s feelings.”

At least 93 cases of lese majeste involving 138 people have been prosecuted since the military seized power in 2014, according to the legal aid group Thai Lawyers for Human Rights. Rights groups say the government’s actions are a way of silencing critics and asserting political control.

Thai Lawyers for Human Rights said in a report this week that use of lthe ese majeste statute, once relatively rare, increased markedly after a military coup in 2006, and escalated further after the 2014 military takeover.

Since 2014, the group said, the law was extended in practice to cover people who clicked “like” or “share” on Facebook, even when they did not write the post in question, and those who made satirical posts about the pets of the monarch.

Tara was convicted for spreading audio files produced by “DJ Banpodj,” an underground internet talk show host known for his strong criticism of the monarchy. “DJ Banpodj” was arrested in 2015, and according to iLaw, at least five other people have been charged with lese majeste for sharing audio clips produced by his network.